The present invention relates generally to evaluating driver attentiveness and, more particularly, to a device for evaluating the attentiveness of a driver in a collision avoidance system in motor vehicles with an electronic control device.
It is generally known that collision warning systems are controlled as a function of the alertness of a driver. Furthermore, there exist a plurality of systems for detecting the alertness of a driver and a plurality of collision avoidance systems, e.g., with an emergency braking action. For example, a collision avoidance system with braking action dependent on the alertness of the driver is disclosed in the DE 198 01 009 C1.
With conventional collision avoidance systems, warnings may be given or action may be taken, when the driver does not deem them to be necessary, since the driver has already recognized the hazardous situation.
An aspect of the invention involves improving collision avoidance systems in terms of driver acceptance. Consistent with the present invention, an electronic control device for evaluating driver attentiveness in a motor vehicle is provided. The motor vehicle may have a collision avoidance system. The electronic device may comprise: an allocation unit that evaluates defined first input data to recognize a driving situation among a plurality of defined driving situations; and a driver monitoring unit operatively coupled to the allocation unit, the driver monitoring unit evaluating defined second input data to assess a degree of situation-adapted attentiveness based on the recognized driving situation, wherein at least one functional unit of the collision avoidance system is controlled by the electronic control device as a function of the assessed degree of situation-adapted attentiveness.
Examples of some potential and defined driving situations are an open road situation, a tailgating situation, a follow-on driving situation, a passing or lane change situation, a panic braking situation, a cutting-in situation and/or, if desired, also combinations of such situations. The defined first input data are, for example, the environmental and/or vehicle-related data, such as the distance to the lead vehicle (target object), the vehicle speed/acceleration/deceleration of one's own vehicle and/or of the target object and/or the steering angle. The defined second input data, which may also be to some extent the same data as the defined first input data, are in particular the data related to the driver's behavior, such as the driver's handling of the steering wheel by measuring the steering angle, the driver's application of the gas pedal and/or brake pedal by means of sensors that already exist for this purpose, eye movements or gestures by means of camera sensors, the driver's actuation of the turn signal, manipulation of the radio, etc. Therefore, any input data that may indicate the operational activities of the driver may also be evaluated at the same time. As an alternative or as an addition, the degree of the situation-adapted attentiveness may also be determined by means of other behavioral patterns of the driver, such as the blink frequency of the eyelids or the body activities. Such evaluations are carried out in a well-known manner by means of, for example, camera systems that are disposed in the passenger compartment. Even the pulse of the driver may be determined in a well-known manner by means of suitable sensors disposed in the steering wheel.
Preferably the degree of the situation-adapted attentiveness is assessed or detected based on a number of different attentiveness categories (e.g., diversion criteria, intent criteria, model-based driver behavior criteria, alertness criteria). Evaluations in terms of the use of the radio, the telephone, or the air conditioning system may be put, for example, into the category—diversion criteria—for the purpose of evaluating the attentiveness.
Evaluations in terms of the driver's steering activity, actuation of the turn signal or change in the driver's direction of vision may be put into the category—intent criteria—for the purpose of evaluating the attentiveness. However, these evaluations may also be used for recognizing the driving situation. Evaluations in terms of the time and intensity, with which the gas or brake pedal was applied, or in terms of the transmission selection control (reverse gear changes) in connection with the situation-specific reaction time windows may be put, for example, into the category—model-based driver behavior criteria—for the purpose of evaluating the attentiveness. Evaluations in terms of the blink frequency of the eyelids, body activities or the pulse may be put, for example, into the category—alertness criteria—for the purpose of evaluating the attentiveness.
Consistent with the present invention, the degree of the situation-adapted attentiveness may be divided into three grade levels. For example, the following grade levels may be defined:
I (not in order): the driver is reacting incorrectly.
II (uncertain, decision cannot be made): the driver's reaction is unpredictable or there exists a driving situation, in which a specific reaction of the driver cannot be expected.
III (in order): driver is reacting correctly.
In particular, the degree of attentiveness may also be expressed in the form of a probability with which the driver will react incorrectly (I), in an undefined manner (II), or correctly (III).
Crucial for recognizing a driving situation is the recognition that the driver is aware of this driving situation. That is, the driver has obviously grasped the driving situation (passively caused the driving situation) or even intentionally introduced this driving situation (actively caused the driving situation). This may include the degree of attentiveness, in particular the attentiveness, adapted to this driving situation, in the immediate past.
For example, a (conscious or rather intentional) passing or lane change situation is detected only if in anticipation the driver has steadily decreased (not suddenly) the driving speed, as is typical for such a situation, before reaching a critical distance. Then it is possible to assume that the attentiveness of the driver is adapted to the passing or lane change situation.
In another example, a panic braking situation (of which the driver is consciously aware or which the driver has obviously grasped) is detected only if prior to the application of the brakes and optionally prior to a decrease in the distance to the target object, the driver initially holds constant at least within specific limits the distance to the target object, as is typical for such a situation; and, if necessary, has reacted to the situation with the typical distance and deceleration-related actions within defined reaction periods after the start of the deceleration action of the lead vehicle. Because then one can assume that the driver's attentiveness is adapted to a panic braking situation. If a conscious panic braking situation is detected, the subsequent actions of the driver during this situation may be evaluated as intentional activities.
Upon recognition of such a conscious (intentional) driving situation (of which the driver is consciously aware), the collision avoidance system may be actuated, but less in the sense of a warning or less in the sense of providing assistance.
If the attentiveness is uncertain or scarcely adapted to the situation, it may be assumed in the above situations that the tailgating situation is unintentional or that the driver is unaware of the tailgating situation or has not grasped this situation. This situation will lead to the collision avoidance system being actuated more in the sense of a warning or in the sense of providing assistance.
Collision avoidance systems are defined as both collision warning systems (with optical, acoustical or haptic warning functions) and as actively engaging collision prevention systems (with automatic braking or steering action). One problem with collision avoidance systems is that, unlike the inattentive driver, the attentive driver does not require any warning or action at all or requires it later. If the attentive driver receives frequent warnings or action during or before a hazardous situation, which he himself has already recognized, the acceptance and hence compliance with the collision avoidance system may experience a steep decline.
It is known that collision warning systems are actuated as a function of the driver's alertness. Furthermore, a plurality of systems for detecting the driver's alertness exist. However, conventional systems do not consider that, first, in different driving situations a varying degree of driver attentiveness is required for the correct reaction and that, second, in different driving situations it would be wise to choose from a plurality of different input data for the purpose of determining the driver's attentiveness. An aspect of the present invention involves determining the driver's attentiveness based on the driving situation. This assessment of the driver's attentiveness is based on the decision whether in a given driving situation the driver is reacting or will react (with high probability) correctly or incorrectly. In this respect, the relevant psychological literature refers to this phenomenon as “correct situational awareness.”
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.